scholarly journals Compact Liquid Crystal Based Tunable Band-Stop Filter with an Ultra-Wide Stopband by Using Wave Interference Technique

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Longzhu Cai ◽  
Huan Xu ◽  
Daping Chu
Keyword(s):  
Liquid Crystal ◽  
Impedance Matching ◽  
Wide Frequency Range ◽  
Ultra Wideband ◽  
New Wave ◽  
Wave Interference ◽  
Rejection Level ◽  
Band Stop Filter ◽  
The Individual ◽  
Uwb Applications

A wave interference filtering section that consists of three stubs of different lengths, each with an individual stopband of its own central frequency, is reported here for the design of band-stop filters (BSFs) with ultra-wide and sharp stopbands as well as large attenuation characteristics. The superposition of the individual stopbands provides the coverage over an ultra-wide frequency range. Equations and guidelines are presented for the application of a new wave interference technique to adjust the rejection level and width of its stopband. Based on that, an electrically tunable ultra-wide stopband BSF using a liquid crystal (LC) material for ultra-wideband (UWB) applications is designed. Careful treatment of the bent stubs, including impedance matching of the main microstrip line and bent stubs together with that of the SMA connectors and impedance adaptors, was carried out for the compactness and minimum insertion and reflection losses. The experimental results of the fabricated device agree very well with that of the simulation. The centre rejection frequency as measured can be tuned between 4.434 and 4.814 GHz when a biased voltage of 0–20 Vrms is used. The 3 dB and 25 dB stopband bandwidths were 4.86 GHz and 2.51 GHz, respectively, which are larger than that of other recently reported LC based tunable BSFs.

scholarly journals Compact Enhanced CPW-Fed Antenna for UWB Applications

2021 ◽  
Vol 10 (1) ◽  
pp. 15-20
Author(s):  
H. Abdi ◽  
J. Nourinia ◽  
C. Ghobadi
Keyword(s):  
Low Cost ◽  
Impedance Matching ◽  
Ground Plane ◽  
Ultra Wideband ◽  
Compact Antenna ◽  
Low Profile ◽  
Rectangular Slit ◽  
Operating Bandwidth ◽  
Uwb Applications ◽  
Operational Range

This paper presents a compact antenna with co-planar waveguide (CPW) feed line for ultra-wideband (UWB) applications. The proposed antenna consists of a beveled radiating patch with wide rectangular slit at its upper side and a partial ground plane with insertion of symmetrically two-step beveled tapers at its center and sides, which provides a wide operating bandwidth. The antenna is integrated with narrow rectangular-shaped parasitic elements with different lengths placed adjacent to radiant patch to significantly enhance the impedance matching and bandwidth, especially at the upper frequencies. The measured results show an |S11| less than -10 dB bandwidth of 2.5-19.8 GHz with 155% fractional bandwidth. Simulation results are in good agreement with experimental measurements, which exhibits the validity of the proposed design approach. Moreover, the proposed CPW-fed antenna shows omnidirectional radiation patterns with stable gain within the operational range. The proposed compact antenna with low profile, light weight, large frequency bandwidth, ease of fabrication and low cost material is suitable for UWB applications.

scholarly journals A CPW-fed Irregular Shaped Hexagonal Patch Antenna with Elliptical Substrate for UWB Applications

2019 ◽  
Vol 9 (2) ◽  
pp. 373-376
Keyword(s):  
Patch Antenna ◽  
Impedance Matching ◽  
Ultra Wideband ◽  
Total Efficiency ◽  
Uwb Antenna ◽  
Radiation Characteristics ◽  
Wide Range ◽  
Uwb Applications ◽  
Novel Design ◽  
Peak Gain

A novel design of Ultra-Wideband (UWB) antenna with irregularly shaped hexagonal patch built on the elliptical-shaped FR-4 laminate with εr = 4.3 and tanδ = 0.025 is presented. The feed mechanism utilized in the structure proposed is modified co-planar waveguide (CPW), the feeding microstrip is tapered near the connecting edge of the patch for better impedance matching. The proposed antenna is compared with the traditional rectangular substrate and found that the elliptical substrate enhances the radiation characteristics of the antenna and is capable of functioning effectively in the range of 3.1 GHz-11.7 GHz, accompanied by the total efficiency > 86% across the whole FCC allocated UWB operating band. The antenna can be used for wide range of UWB applications as it exhibits good omnidirectional characteristics with a realized peak gain of 4.178dB and an average realized gain of 3.063dB. The simulation work of the antenna is accomplished using CST Studio (v. 2014).

scholarly journals Mutual Coupling Reduction Using a Protruded Ground Branch Structure in a Compact UWB Owl-Shaped MIMO Antenna

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
A. Mchbal ◽  
N. Amar Touhami ◽  
H. Elftouh ◽  
A. Dkiouak
Keyword(s):  
Mutual Coupling ◽  
Impedance Matching ◽  
Ground Plane ◽  
Multiple Input Multiple Output ◽  
Monopole Antenna ◽  
Ultra Wideband ◽  
Impedance Bandwidth ◽  
Mimo Antenna ◽  
Input Multiple Output ◽  
Uwb Applications

A compact ultra-wideband (UWB) multiple input-multiple output (MIMO) antenna with high isolation is designed for UWB applications. The proposed MIMO antenna consists of two identical monopole antenna elements. To enhance the impedance matching, three slots are formed on the ground plane. The arc structure as well as the semicircle with an open-end slot is employed on the radiating elements the fact which helps to extend the impedance bandwidth of the monopole antenna from 3.1 up to 10.6 GHz, which corresponds to the UWB band. A ground branch decoupling structure is introduced between the two elements to reduce the mutual coupling. Simulation and measurement results show a bandwidth range from 3.1 to 11.12 GHz with |S11_|<−15 dB, |S21_|<−20 dB, and ECC < 0.002.

Multiband rectangular-shaped ring antenna embedded with inverted S- and C-shaped strips for WLAN/WiMAX/UWB applications

2014 ◽  
Vol 7 (1) ◽  
pp. 81-86 ◽  
Author(s):  
Davinder Parkash ◽  
Rajesh Khanna
Keyword(s):  
Return Loss ◽  
Impedance Matching ◽  
Research Work ◽  
Fair Agreement ◽  
Ultra Wideband ◽  
Low Profile ◽  
Radiating Element ◽  
Ring Antenna ◽  
Parametric Studies ◽  
Uwb Applications

This research work presents a microstrip-fed antenna that is small, low-profile, planar, and suitable for WLAN/WiMAX and partially ultra-wideband (UWB) applications. The radiating element of the proposed antenna consists of rectangular-shaped ring embedded with a three inverted “S”-shaped and inverted “C”-shaped strips. This antenna is capable of generating penta bands having good impedance matching with wideband characteristics. Prototype of the proposed antenna has been designed, simulated, fabricated, and tested. The overall small size of the antenna is 24.75 mm × 27.39 mm × 1.6 mm with volumetric size of 1 cm3. To understand the characteristics of the proposed antenna, the parametric studies are being performed. The return loss of the proposed antenna shows fair agreement with the simulated and measured results.

Compact stepped slot antenna for ultra-wideband applications

2021 ◽  
pp. 1-7
Author(s):  
B. Hammache ◽  
A. Messai ◽  
I. Messaoudene ◽  
T. A. Denidni
Keyword(s):  
Radiation Pattern ◽  
Impedance Matching ◽  
Ultra Wideband ◽  
Slot Antenna ◽  
Impedance Bandwidth ◽  
Back Side ◽  
Compact Size ◽  
Measurement Results ◽  
Operating Bandwidth ◽  
Uwb Applications

Abstract In this paper, a compact stepped slot antenna for ultra-wideband (UWB) applications is proposed. A very small size and UWB bandwidth operation are achieved by integrating a stepped slot in the back side of the antenna. This stepped slot is excited by using a 50 Ω-feed line in the top side of the antenna. The antenna is characterized by an impedance bandwidth between 3.05 GHz and more than 12 GHz. The dimensions of the antenna are 17 mm × 8 mm × 1.27 mm, which leads to the most compact size compared with other works in the literature. The integrated stepped slot is divided into additional elementary slots, where each elementary slot has a matching point. Adding these elementary slots allows to increase further the operating bandwidth. The radiation pattern of the compact stepped slot antenna is omnidirectional in the H-plane and bidirectional in the E-plane. The measurement results agree well with the simulated ones in terms of impedance matching and radiation pattern.

scholarly journals Isolation Enhancement Using a Hybrid Technique in an Eight-Element UWB MIMO Antenna Design

2020 ◽  
Vol 9 (3) ◽  
pp. 56-65
Author(s):  
A. Mchbal ◽  
N. Amar Touhami ◽  
H. Elftouh ◽  
A. Dkiouak
Keyword(s):  
Impedance Matching ◽  
Multiple Input Multiple Output ◽  
Correlation Coefficients ◽  
Ultra Wideband ◽  
Hybrid Technique ◽  
Good Efficiency ◽  
Mimo Antenna ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Uwb Applications

A high order multiple input multiple output (MIMO) antenna assembly is designed for Ultra-Wideband (UWB) applications. The antenna configuration is based on a peculiar arrangement of the radiating elements. A defected microstrip structure is also introduced on the feedlines. The use of a novel technique, the so-called ports-shift, is here discussed. In the proposed antenna, a protruded ground branch structure is employed in combination of three parasitic stubs so as to enhance isolation and impedance matching over the UWB frequency band. The results show that the presented antenna exhibits a good impedance matching which is about -10 dB with a high mutual coupling 15 dB, and envelope correlation coefficients (ECC) smaller than 0.15. The antenna also exhibits good diversity gain of about 9.5, and a good efficiency that varied between 56% and 91% and total active reflection coefficient of less than -20 dB. Which makes it a good candidate for UWB applications.

scholarly journals Highly Compact Design of Trimmed Patch with Modified Partial Ground Structure for Extreme-Wideband Systems

2017 ◽  
Vol 7 (5) ◽  
pp. 1918-1921
Author(s):  
H. Alsaif
Keyword(s):  
Impedance Matching ◽  
Ground Plane ◽  
Substrate Material ◽  
Ultra Wideband ◽  
Operating Frequency ◽  
Radiation Characteristics ◽  
Total Size ◽  
Compact Design ◽  
Uwb Applications ◽  
Wide Operating

In this paper, a novel highly compact microstrip monopole antenna with adjusted ground plane for ultra-wideband (UWB) applications is proposed. The patch antenna is composed of a trimmed radiator and rectangular ground plane with four slots providing relatively extreme wide operating frequency from 2.8 till 16.2 GHz based on -10 dB criteria. The high matching impedance in the design results in ultra-wide bandwidth that covers the entire BW allocated by FCC for UWB applications. At the same time, the presented antenna is distinguished by significantly miniaturized structure with total size of 13 mm x 10 mm printed on a substrate material of Rogers Duriod RT 5880 LZ with relative permittivity of εr=1.9 and loss tangent δ of 0.0009. The suggested antenna is appropriate for miniature wireless gadgets. The patch has been investigated, and optimized in terms of operating frequency, impedance matching, radiation characteristics, structure size, and fabrication cost.

A Tapered Fork-Shaped Antenna With Small Ground Plane for UWB Applications

2021 ◽  
Vol 13 (1) ◽  
pp. 13-24
Author(s):  
Amro A. Nour ◽  
Ali Bostani ◽  
Girish Awadhwal
Keyword(s):  
Finite Element ◽  
Impedance Matching ◽  
Ground Plane ◽  
Wide Band ◽  
Federal Communications Commission ◽  
Ultra Wideband ◽  
Design Parameters ◽  
Uwb Antenna ◽  
Bandwidth Enhancement ◽  
Uwb Applications

A tapered fork-shaped antenna having small ground for ultra-wide band (UWB) antenna is proposed in this paper. Finite element method has been successfully employed to simulate and optimize the feed line, ground, and tapered fork-shaped diameter to enhance the performance of the antenna in terms of bandwidth obviously for the ultra-wideband purposes. An acceptable impedance matching performance has been achieved, which is a band wider than the UWB band that is defined by the Federal Communications Commission (FCC). In this paper, the detailed design parameters including the key elements in bandwidth enhancement is presented. The results of the finite element simulations have been presented as well indicating the return loss and radiation pattern of the proposed antenna.

Isolation Enhancement between Ports of a Compact Ultra-wideband MIMO Antenna

2021 ◽  
Vol 36 (1) ◽  
pp. 61-66
Author(s):  
Yantao Yu ◽  
Shenshen Mao ◽  
Meng Li ◽  
Danting He
Keyword(s):  
Impedance Matching ◽  
Multiple Input Multiple Output ◽  
Dielectric Substrate ◽  
Spatial Diversity ◽  
Ultra Wideband ◽  
Back Side ◽  
Mimo Antenna ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Uwb Applications

In this paper, a novel compact multiple-input multiple-output (MIMO) antenna with enhanced port isolation is proposed for ultra-wideband (UWB) applications. The UWB MIMO antenna contains two coplanar annular monopoles etched on the front side of the FR-4 substrate. The dielectric substrate has a relative permittivity of 4.4 and a size of 80 mm × 40 mm × 1.6 mm. The irregular ground is printed on the back side of the substrate. In order to enhance the port isolation between the two monopoles, the expanded ground is exploited in the proposed design. In addition, the ground is etched with some slots to achieve good impedance matching. Both the simulated and measured results show that the proposed antenna achieves good impedance matching as well as high port isolation over the entire UWB band. Moreover, the proposed antenna has good spatial diversity characteristics. In summary, the proposed UWB MIMO antenna can be well applied to the ultra-wideband wireless communication system.

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